elevation gain has huge deviation

skyhark · July 10, 2020, 01:53:56 AM

Hello

When upgrade to version 8.0, I found the elevation gain has huge deviation with after correct altitude, see attached file, where I should set up for this? thanks

matt · July 10, 2020, 07:51:37 AM

Hi,
i noticed as similar problem, with "Elevation gain" and "Elevation loss" (and Ascent/Descent speed) beeing far to high from what i expect.

Most obvious for me, if i load e.g. a one-way track from a mountain down to sealevel (with some up-hill on the way), into OruxMaps. I have loaded such a track on two phones. Both phones show correctly max (1261m) and min (4m) altitude, but

My old phone with "7.4.22-donate" shows "Elevation gain = 1225m", "Elevation loss = 2348"
My new phone with "8.0.4 GP" shows "Elevation gain = 2493m", "Elevation loss = 3635"

Also websites, where i upload that track to, are much much closer to the statistics shown on old "7.4.22-donate"

ken888 · July 15, 2020, 07:44:49 AM

I also am finding that all Oruxmaps elevations are incorrect. Oruxmaps elevations are much higher than the elevations shown on GPSStatus app and contours on a topo map with 10 metre contours (Not SRTM based elevations). Eg OM says 230m whereas the topo map says 170m. Ouxmaps v8.0.3 GP. Thanks for a great app.

orux · August 01, 2020, 06:59:13 PM

Quote from: ken888 on July 15, 2020, 07:44:49 AM
I also am finding that all Oruxmaps elevations are incorrect. Oruxmaps elevations are much higher than the elevations shown on GPSStatus app and contours on a topo map with 10 metre contours (Not SRTM based elevations). Eg OM says 230m whereas the topo map says 170m. Ouxmaps v8.0.3 GP. Thanks for a great app.

In the latest versions there were some changes to the height calculations, which seem to work better under normal conditions, but I am seeing that it can fail, especially if:

--Dem files are used for the altitude, the 'interpolate DEM altitude' option has not been selected.
--GPS is used, but gives values with very wide vertical oscillations.

If you send me an example in GPX format, I can continue investigating -> oruxuro@gmail.com

I remind you that afterwards you can correct the altitudes of the Tracks, using DEM files (on the web there are good sources of 1 "DEM files) and smoothing the profile. With this last procedure you can correct the profiles quite well, if they have sawtooth shape, using a high filtering radius.

orux

ken888 · August 05, 2020, 05:56:12 AM

My problem was incorrect elevations in Oruxmaps. This was fixed by selecting 'Use Geoid altitude' in Oruxmaps - Global settings - Sensors - GPS (tap it) - Use Geoid altitude. Thanks Orux.

notbru · August 05, 2020, 08:51:35 PM

Hello,
in 8.0.5beta2 the option 'interpolate DEM altitude' is missing.
Without that, elevation gain/loss becomes to big.

Thank you for this great app!
notbru

skyhark · August 08, 2020, 08:59:13 AM

Whether after version 8.0 the option of "FUSED LOCATIONS PROVIDER" default is checked ? un-checked this item then try to record the elevation gain and on-line correct the result is approach real elevation gain already!

orux · August 11, 2020, 09:50:09 AM

Quote from: skyhark on August 08, 2020, 08:59:13 AM
Whether after version 8.0 the option of "FUSED LOCATIONS PROVIDER" default is checked ? un-checked this item then try to record the elevation gain and on-line correct the result is approach real elevation gain already!

Hello!
That option is checked because some manufacturers force apps to use that location provider if the app wants to work in the background.

It was a stupid decision, I think that has changed, but the problem with Android updates (I mean the missing of updates) is that there will be a lot of devices stuck to that way of work for years.

orux